1. Field of the Invention
The present disclosure relates to a liquid crystal display (LCD), and more particularly, to an LCD using an in-cell touch mode and a manufacturing method thereof.
2. Discussion of the Related Art
Specific examples of flat panel displays include an LCD, a plasma display panel (PDP) device, a field emission display (FED) device, and an electroluminescence display device (ELD). These devices commonly include a flat display panel as an essential element, and the flat display panel has a structure in which a pair of transparent insulating substrates are attached in a facing manner with an emission or polarization material layer interposed therebetween.
Among them, the LCD displays an image by adjusting light transmittance of liquid crystal by using an electric field. To this end, an image display device includes a display panel having a liquid cell, a backlight unit irradiating light to the display panel, and a driving circuit for driving the liquid crystal cell.
Recently, demand for adding a touch panel which recognizes a touched portion through a user's hand or a separate input unit and transmits separate information corresponding thereto has increased. Currently, such a touch panel is applied in a form of being attached to an external surface of a display device.
Also, according to a touch sensing scheme, a touch panel is classified as a resistive touch panel, a capacitive touch panel, and an infrared sensing type touch panel, and recently, in consideration of ease in manufacturing scheme and sensing power, the capacitive touch panel, as a small mode, has come to prominence.
As the capacitive scheme, a mutual capacitive sensing scheme is used in order to recognize a multi-touch.
Among touch sensors using the capacitive sensing scheme, an in-cell touch type touch sensor has recently emerged. Here, the in-cell touch type touch sensor is a technique of implementing a touch operation by forming a touch sensor on a lower substrate.
Recently, the in-cell touch technique is applied to LCDs in various driving modes.
The in-cell touch sensors using the capacitive scheme has a limitation in application to a TN mode LCD among LCDs in various driving modes.
The reason is because, the TN mode LCD has a structure in which a gate electrode, an active layer, source and drain electrodes, and a pixel electrode are formed on a lower substrate and a black matrix, a color filter, a common electrode, and a columnar spacer are formed on an upper substrate.
Thus, in a case in which the in-cell touch scheme is applied to the TN mode LCD, when a user touches an upper portion of a color filter, a touch signal is blocked by the common electrode provided on an upper substrate of a TN panel, making it difficult to implement a touch function. Also, there is a difficulty in configuring a touch electrode, while maintaining the TN structure within a lower substrate.